Net neutrality is the idea that all traffic on the internet is treated equally. In 2015, under President Barack Obama, a Democrat-led FCC passed rules that barred broadband companies from slowing down or blocking access to certain websites or services. It also prohibited internet companies from charging a fee to access customers more quickly.

Supporters of net neutrality say the rules are necessary to ensure broadband companies don’t abuse their power as gatekeepers of the internet. Companies like Facebook, Google, and Twitter supported the rules. But broadband providers say the rules were too onerous and stifled investment. Broadband providers like AT&T, Comcast, and Verizon support the FCC’s repeal of the rules.

The publication of the repeal in the Federal Register is an important procedural milestone because it sets into motion a countdown for challenging the rule change. Lawsuits challenging the repeal can be filed as soon as the rules have been published. Several net neutrality supporters and attorneys general in more than 20 states have already filed petitions with the court. But they will have to refile their lawsuits within a 10-day window following the publication of the rules in the Federal Register.

The publication of the order to repeal the rules also starts the clock on a deadline for Congress to pass legislation that could nullify the FCC’s actions. Using the Congressional Review Act, Congress has 60 legislative days to pass a resolution that would reverse the repeal and keep the rules in place. Democrats say with the promise that Republican Susan Collins of Maine will side with them, they have 50 votes in the Senate under the CRA.

They need just one more vote to pass a measure in the Senate. But the legislation would still have to pass the House of Representatives where it would likely face a much higher hurdle. And President Donald Trump would also have the option to veto if it got through the House.

Meanwhile several states such as New Jersey, Montana and New York are making their own net neutrality policies. Governors in these states have signed executive orders requiring service providers that do business with the state adhere to the principles of net neutrality. That means broadband providers wouldn’t be allowed to throttle traffic or create internet “fast lanes.”

FCC commissioner Mignon Clyburn, a Democrat who has defended the 2015 rules, said she is “both disappointed and hopeful. Disappointed that this is one more anti-consumer notch on this FCC’s belt, but hopeful that the arc of history is bent in favor of net neutrality protections.”

“Whether it is litigation, state action, or some other mechanism that brings it about, I am sure that robust net neutrality protections will prevail with the American public,” she added.